EXAM 3 Sex Linked Transmission Lec Flashcards
(36 cards)
What is the role of chromosomes in sex determination?
Chromosomes play a role in sex determination in many animal species.
What is the difference between homogametic and heterogametic?
Homogametic refers to individuals with two identical sex chromosomes, while heterogametic refers to those with two different sex chromosomes.
What does the Y chromosome determine in mammals?
The Y chromosome determines maleness (Male: XY, Female: XX).
What are the sex chromosomes in birds?
The sex chromosomes in birds are designated Z and W.
How do the sex chromosomes determine gender in birds?
W chromosome determines femaleness (Male: ZZ, Female: ZW).
What is the sex determination system in some insects?
In some insects, males are XO and females are XX.
What is the sex determination system in fruit flies?
In fruit flies, males are XY and females are XX.
What determines maleness in fruit flies?
The ratio between the X chromosomes and the number of sets of autosomes (X/A) determines maleness.
What is the X/A ratio for a male fruit fly?
If X/A=0.5, the fly becomes a male.
What is the X/A ratio for a female fruit fly?
If X/A=1.0, the fly becomes a female.
What are male bees known as?
Males are known as drones.
What is the ploidy of male bees?
Males are haploid.
How are female bees produced?
Females include worker bees and queen bees, produced from fertilized eggs.
What are sex-linked genes?
Genes found on one of the two types of sex chromosomes but not on both.
What does it mean for males to be hemizygous?
Males have only one copy of the X chromosome.
Who confirmed the chromosome theory of inheritance?
Thomas Hunt Morgan confirmed the chromosome theory of inheritance.
What organism did Morgan use for his experiments?
Morgan used the fruit fly Drosophila melanogaster.
What was the significant result of Morgan’s experiments?
A male fruit fly with white eyes rather than the normal red eyes.
What are reciprocal crosses?
Crosses between different strains in which the sexes are reversed.
What do reciprocal crosses reveal?
They reveal whether a trait is carried on a sex chromosome or an autosome.
Do X-linked traits behave identically in reciprocal crosses?
No, X-linked traits do not behave identically in reciprocal crosses.
What do the X and Y chromosomes contain at one end?
Short regions of homology that promote pairing in meiosis I in spermatogenesis.
What is the inheritance pattern of genes in the homologous region of X and Y chromosomes?
These genes follow a pseudoautosomal pattern of inheritance.
How do males inherit their X chromosome?
Males get their X from their mother.
